The study, published tomorrow in the journal Science, claims to be the first to provide strong evidence of a link between local fish supply and bush-meat hunting. (See photographs of bush-meat hunting in Africa. Warning: photos include depictions of butchered animals.)

Lead author Justin Brashares, assistant professor of ecosystems science at the University of California, Berkeley, says it's likely that other West African countries are similarly affected.

"If people aren't able to get their protein from fish, they'll turn elsewhere for food and economic survival," he said. "Unfortunately the impacts on wild game resources are not sustainable."

Using data from six Ghanaian nature reserves between 1970 and 1998, the research team found a massive 76 percent fall in abundance for 41 species of larger mammals.

Over a similar period the marine fish catch in Ghana ranged from 230,000 to 480,000 tons annually, varying by as much as 24 percent in consecutive years. When regional fish supplies dropped, reports of bush-meat hunters on the reserves were seen to rise. Likewise, bush meat for sale at 12 local markets was found to increase when fish supplies fell.

Brashares says wild animals that suffered most were large carnivores such as lions, leopards, and hyenas; primates including colobus and mona monkeys; and several herbivores (hippos, giant hogs, and bongo antelopes).

Fishing Funded by European Union

The researchers note that subsidized foreign fleets have taken much of the blame for Ghana's depleted fish stocks, particularly those from European Union (EU) countries. The study shows that financial aid for EU fishing vessels in foreign waters rose from around 6 million U.S. dollars in 1981 to more than 350 million dollars in 2001.

Brashares says studies have shown these subsidies artificially increase profitability for EU companies operating in African waters. He added, "If it weren't for this financial support, these studies suggest, it wouldn't be worthwhile for EU fleets to head to West Africa." In 1996, for instance, the equivalent of 229 million U.S. dollars was paid to African governments by the EU for access agreements to African waters, according to the Worldwatch Institute in Washington D.C.